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IEEE Workshop on Signal Processing Systems (SIPS)

作者： Qi Ding Alan V. Oppenheim Petros T. Boufounos Simon Gustavsson Jeffrey A. Grover Thomas A. Baran William D. Oliver Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA Mitsubishi Electric Research Laboratories Cambridge MA USA Department of Physics Massachusetts Institute of Technology Cambridge MA USA Atlantic Quantum Cambridge MA USA

ISBN: (数字)9798350373752

ISBN: (纸本)9798350373769

Chebyshev approximation problems are fundamen-tal in approximation theory and are integral to various engi-neering applications. In this study, we suggest that weighted Chebyshev approximation (WCA) can be effectively applied to designing quantum gates. Specifically, we examine a class of two-qubit gates in superconducting qubits known as controlled-phase (CPHASE) gates, which leverage interactions between higher levels controlled by baseband flux pulses. We frame the design of CPHASE gates as a pulse design problem and propose Chebyshev pulses, generated through WCA, as an alternative solution. We utilize an illustrative example to demonstrate our process of designing a Chebyshev pulse with WCA, then contrast it with a benchmark Slepian pulse for comparison. We find that Chebyshev pulses can facilitate faster CPHASE gates while ensuring leakage errors remain below the desired threshold.

关键词： Baseband Simulation Design methodology Conferences Qubit Logic gates Chebyshev approximation Benchmark testing Signal processing Iterative methods

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Spin-wave eigenmodes in nanoscale magnetic tunnel junctions with perpendicular magnetic anisotropy

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Physical Review Applied 2025年第3期23卷 034086-034086页

作者： Andrea Meo Chengcen Sha Emily Darwin Riccardo Tomasello Mario Carpentieri Ilya N. Krivorotov Giovanni Finocchio Department of Electrical and Information Engineering Politecnico di Bari I-70125 Bari Italy Department of Physics and Astronomy University of California Irvine California 92697 USA Magnetic & Functional Thin Films Lab Empa Swiss Federal Laboratories for Materials Science and Technology CH-8600 Dübendorf Switzerland Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina I-98166 Messina Italy

Magnetic tunnel junctions (MTJs) are key enablers of spintronic technologies used in a variety of applications, including information storage, microwave generation and detection, and unconventional computing. Here, we present experimental and theoretical studies of the quantized spin wave eigenmodes in perpendicular MTJs focusing on the coupled magnetization dynamics in the free (FL) and reference (RL) layers of the MTJ, where the RL is a synthetic antiferromagnet (SAF). Spin-torque ferromagnetic resonance (ST-FMR) measurements reveal the excitation of two spin-wave eigenmodes in response to an applied microwave current. These modes show opposite frequency shifts as a function of an out-of-plane magnetic field. Our micromagnetic simulations accurately reproduce the dependence of the mode frequencies on the magnetic field and reveal the spatial profiles of the excitations in the FL and RL. The FL and RL modes generate rectified voltage signals of opposite polarity, which makes this device a promising candidate for a tunable dual-frequency microwave signal detector. The simulations show that a weak interlayer exchange coupling within the SAF enhances the mode amplitudes. We also calculate the response of the detector as a function of an in-plane magnetic field bias and find that its sensitivity significantly grows with increasing field strength. We experimentally confirm this prediction via ST-FMR measurements as a function of the in-plane magnetic field. Our results provide a deeper understanding of the quantized spin-wave eigenmodes in nanoscale MTJs with perpendicular magnetic anisotropy and demonstrate the potential of these devices for frequency-selective dual-channel microwave signal detectors.

关键词： Spin waves

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Analysis of Coding Gain Due to In-Loop Reshaping

arXiv

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arXiv 2023年

作者： Wong, Chau-Wai Fu, Chang-Hong Xu, Mengting Su, Guan-Ming The Department of Electrical and Computer Engineering NC State University NC27695 United States The School of Electronic and Optical Engineering Nanjing University of Science and Technology Jiangsu210094 China The Dolby Laboratories SunnyvaleCA94085 United States

Reshaping, a point operation that alters the characteristics of signals, has been shown capable of improving the compression ratio in video coding practices. Out-of-loop reshaping that directly modifies the input video signal was first adopted as the supplemental enhancement information (SEI) for the HEVC/H.265 without the need to alter the core design of the video codec. VVC/H.266 further improves the coding efficiency by adopting in-loop reshaping that modifies the residual signal being processed in the hybrid coding loop. In this paper, we theoretically analyze the rate–distortion performance of the in-loop reshaping and use experiments to verify the theoretical result. We prove that the in-loop reshaping can improve coding efficiency when the entropy coder adopted in the coding pipeline is suboptimal, which is in line with the practical scenarios that video codecs operate in. We derive the PSNR gain in a closed form and show that the theoretically predicted gain is consistent with that measured from experiments using standard testing video sequences. © 2023, CC BY-NC-SA.

关键词： Image compression

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Statistically characterizing robustness and fidelity of quantum controls and quantum control algorithms

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Physical Review A 2023年第3期107卷 032606-032606页

作者： Irtaza Khalid Carrie A. Weidner Edmond A. Jonckheere Sophie G. Shermer Frank C. Langbein School of Computer Science and Informatics Cardiff University Cardiff CF24 4AG United Kingdom Quantum Engineering Technology Laboratories H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering University of Bristol Bristol BS8 1FD United Kingdom Department of Electrical and Computer Engineering University of Southern California Los Angeles California 90089 USA Department of Physics Swansea University Swansea SA2 8PP United Kingdom

Robustness of quantum operations or controls is important to build reliable quantum devices. The robustness-infidelity measure (RIMp) is introduced to statistically quantify in a single measure the robustness and fidelity of a controller as the pth order Wasserstein distance between the fidelity distribution of the controller under any uncertainty and an ideal fidelity distribution. The RIMp is the pth root of the pth raw moment of the infidelity distribution. Using a metrization argument, we justify why RIM1 (the average infidelity) is a good practical robustness measure. Based on the RIMp, an algorithmic robustness-infidelity measure (ARIM) is developed to quantify the expected robustness and fidelity of controllers found by a control algorithm. The utility of the RIM and ARIM is demonstrated on energy landscape controllers of spin-12 networks subject to Hamiltonian uncertainty. The robustness and fidelity of individual controllers as well as the expected robustness and fidelity of controllers found by different popular quantum control algorithms are characterized. For algorithm comparisons, stochastic and nonstochastic optimization objectives are considered. Although high fidelity and robustness are often conflicting objectives, some high-fidelity, robust controllers can usually be found, irrespective of the choice of the quantum control algorithm. However, for noisy or stochastic optimization objectives, adaptive sequential decision-making approaches, such as reinforcement learning, have a cost advantage compared to standard control algorithms and, in contrast, the high infidelities obtained are more consistent with high RIM values for low noise levels.

关键词： Machine learning Quantum computation Quantum control Quantum engineering Quantum information theory

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High-Fidelity CFD Verification Workshop 2024: Shock-Dominated Flows

High-Fidelity CFD Verification Workshop 2024: Shock-Dominate...

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AIAA Aviation Forum and ASCEND, 2024

作者： Huang, Tianci Zahr, Matthew J. Holst, Kevin Freels, James D. Baker, A.J. Batten, Paul Bachchan, Nili Brad Maeng, Jungyeoul Fisher, Travis C. Kim, Dongseok Yune, Kyeol Kim, Chongam Kim, Juhyun Park, Jaehyeon Jee, Solkeun White, William J. Johnsen, Eric Department of Aerospace and Mechanical Engineering University of Notre Dame Notre DameIN46556-5637 United States Department of Electrical Engineering and Computer Science University of Tennessee KnoxvilleTN37996 United States Department of Mechanical Aerospace and Biomedical Engineering University of Tennessee KnoxvilleTN37996 United States Metacomp Technologies Inc. 31365 Oak Crest Drive #250 Westlake Village CA91361 United States Computational Thermal and Fluid Mechanics Sandia National Laboratories AlbuquerqueNM87185 United States Department of Aerospace Engineering Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of Department of Aerospace System Engineering Sejong University Neungdong-ro Gwangjin-gu Seoul05006 Korea Republic of School of Mechanical Engineering Gwangju Institute of Science and Technology 123 Cheomdan-gwagi-ro Kuk-gu Gwangju61005 Korea Republic of University of Michigan Ann ArborMI48109 United States

This manuscript presents the test problems and results of the shock-dominated flow test suite of the first High-Fidelity CFD Verification Workshop held on January 6-7, 2024. © 2024, American Institute of Aeronaut... 详细信息

ISBN: (纸本)9781624107160

关键词： Shock testing

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Beam Structured Signal Detection for HF Skywave Massive MIMO Communications

Beam Structured Signal Detection for HF Skywave Massive MIMO...

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IEEE Conference on Vehicular technology (VTC)

作者： Ding Shi Linfeng Song Xiqi Gao Jiaheng Wang Mats Bengtsson Geoffrey Ye Li National Mobile Communications Research Laboratory Southeast University Nanjing China Purple Mountain Laboratories Nanjing China School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm Sweden Department of Electrical and Electronic Engineering Imperial College London London U.K.

In this paper, we investigate signal detection for HF skywave massive multiple-input multiple-output (MIMO) communications with orthogonal frequency division multiplexing (OFDM) modulation. We first introduce beam based channel model (BBCM) in the space domain and reveal the sparsity of the channel in the space-beam domain. Based on the BBCM in the space domain, we propose a beam structured detector (BSD) for each subcarrier. Specifically, we prove that the space domain detector design can be transformed to that of a beam domain detector without sacrificing optimality, and the asymptotically optimal space domain detector is beam structured with a low-dimensional beam domain detector, thus significantly reducing the design and implementation complexities. Furthermore, we provide a beam selection criterion to choose the beams that are used for the BSD. Simulation results demonstrate the low complexity and satisfactory performance of the proposed detector.

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Multi-color solitons and frequency combs in microresonators

arXiv

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arXiv 2024年

作者： Menyuk, Curtis R. Shandilya, Pradyoth Courtright, Logan Moille, Grégory Srinivasan, Kartik Computer Science and Electrical Engineering Department University of Maryland Baltimore County BaltimoreMD21250 United States Joint Quantum Institute NIST University of Maryland College ParkMD20742 United States Microsystems and Nanotechnology Division National Institute of Standards and Technology GaithersburgMD20899 United States

Multi-color solitons that are parametrically created in dual-pumped microresonators generate interleaved frequency combs that can be used to obtain combs at new frequencies and when synchronized can be used for low-noise microwave generation and potentially as an element in a chip-scale clockwork. Here, we first derive three-wave equations that describe multi-color solitons that appear in microresonators with a nearly quartic dispersion profile. These solitons are characterized by a single angular group velocity and multiple angular phase velocities. We then use these equations to explain the interleaved frequency combs that are observed at the output of the microresonator. Finally, we used these equations to describe the experimentally-observed soliton-OPO effect. In this effect, the pump frequency comb interacts nonlinearly with a signal frequency comb to create an idler frequency comb in a new frequency range, analogous to an optical parametric oscillation (OPO) process. We determine the conditions under which we expect this effect to occur. We anticipate that the three- wave equations and their extensions will be of use in designing new frequency comb systems and determining their stability and noise performance. © 2024, CC BY.

关键词： Solitons

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Sensing-Communication-Computing-Control Closed-Loop Optimization for 6G Unmanned Robotic Systems

arXiv

引用

arXiv 2024年

作者： Fang, Xinran Lei, Chengleyang Feng, Wei Chen, Yunfei Xiao, Ming Ge, Ning Wang, Cheng-Xiang State Key Laboratory of Space Network and Communications Department of Electronic Engineering Tsinghua University Beijing100084 China Department of Engineering University of Durham DurhamDH1 3LE United Kingdom Department of Information Science and Engineering School of Electrical Engineering and Computer Science Royal Institute of Technology Sweden National Mobile Communications Research Laboratory School of Information Science and Engineering Southeast University Nanjing210096 China Purple Mountain Laboratories Nanjing211111 China

Rapid advancements in field robots have brought a new kind of cyber physical system (CPS)-unmanned robotic system-under the spotlight. In the upcoming sixth-generation (6G) era, these systems hold great potential to replace humans in hazardous tasks. This paper investigates an unmanned robotic system comprising a multi-functional unmanned aerial vehicle (UAV), sensors, and actuators. The UAV carries communication and computing modules, acting as an edge information hub (EIH) that transfers and processes information. During the task execution, the EIH gathers sensing data, calculates control commands, and transmits commands to actuators-leading to reflex-arc-like sensing-communication-computing-control (SC3) loops. Unlike existing studies that design SC3loop components separately, we take each SC3loop as an integrated structure and propose a goal-oriented closed-loop optimization scheme. This scheme jointly optimizes uplink and downlink (UL&DL) communication and computing within and across the SC3loops to minimize the total linear quadratic regulator (LQR) cost. We derive optimal closed-form solutions for intra-loop allocation and propose an efficient iterative algorithm for inter-loop optimization. Under the condition of adequate CPU frequency availability, we derive an approximate closed-form solution for inter-loop bandwidth allocation. Simulation results demonstrate that the proposed scheme achieves a two-tier task-level balance within and across SC3loops. © 2024, CC0.

关键词： Unmanned aerial vehicles (UAV)

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Micromagnetic study of the frequency response of skyrmions in magnetic multilayers

Micromagnetic study of the frequency response of skyrmions i...

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IEEE Conference on Nanotechnology

作者： Eleonora Raimondo Emily Darwin Davi Rodrigues Anna Giordano Mario Carpentieri Giovanni Finocchio Riccardo Tomasello Istituto Nazionale di Geofisica e Vulcanologia Rome Italy Empa Swiss Federal Laboratories for Materials Science and Technology Dubendorf Switzerland Department of Electrical and Information Engineering Politecnico di Bari Bari Italy Department of Engineering University of Messina Messina Italy Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina Messina Italy

ISBN: (数字)9798350386240

ISBN: (纸本)9798350386257

Magnetic skyrmions are localized magnetization entities with a particle-like feature due to the topological stability. Often considered as promising information carriers, they can exhibit a variety of dynamics beyond the rigid translational motion, such as breathing mode and gyration. These modes are at the key ingredient for skyrmion-based oscillators and detectors. These modes become even more interesting when considering skyrmions in magnetic multilayers. Here, we analyze, within a micromagnetic framework, the frequency response of skyrmions in different magnetic multilayers, as a function of the number of ferromagnetic repetitions and/or number of skyrmions. We observe the presence of a main frequency peak related to the breathing mode, as well as the emergence of additional peaks linked to the number of repetitions and skyrmions. Our achievement can be useful for the design of the next generation of microwave devices based on skyrmions. 1

关键词： Magnetic multilayers Microwave devices Nonhomogeneous media Frequency response Microwave oscillators Stability analysis Micromagnetics

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An Enhanced Resource Selection Scheme for Efficient Intra-Platoon Message Delivery

An Enhanced Resource Selection Scheme for Efficient Intra-Pl...

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IEEE Conference on Global Communications (GLOBECOM)

作者： Bingying Wang Jun Zheng Cheng Li School of Electronics and Information Engineering Nanjing University of Information Science and Technology Nanjing China National Mobile Communications Research Laboratory Frontiers Science Center for Mobile Information Communication and Security Southeast University Nanjing China Purple Mountain Laboratories Nanjing China School of Engineering Science Simon Fraser University Burnaby Canada Department of Electrical and Computer Engineering Memorial University St. John's Canada

ISBN: (数字)9798350351255

ISBN: (纸本)9798350351262

This paper proposes an enhanced resource selection (eInP-RS) scheme for efficient intra-platoon message delivery of cooperative awareness messages (CAMs) and decentralized environmental notification messages (DENMs). To achieve this goal, the eInP-RS scheme allows each vehicle to transmit CAM and DENM packets on a C-V2X channel (CH1) and an 802.11p channel (CH2), separately, and introduces four mechanisms to enhance the standardized sensing-based SPS scheme. A contention window (CW) size adjustment mechanism is introduced to enable a vehicle to adjust its CW size according to the information it collects on CH1 in order to avoid potential packet collisions on CH2; a resource partition mechanism is introduced to divide frequency-time resources in a selection window into two sets in order for vehicles moving in opposite directions to select different resources and thus avoid potential merging collisions on CH1; an intra-platoon cooperation mechanism is introduced to enable the PL of a platoon to know the resource and channel occupation information of the platoon's hidden nodes on CH1 and CH2; and a packet collision detection mechanism is used to enable a non-platoon vehicle to detect packet collisions occurring on both channels after a lane-changing maneuver to avoid potential merging collisions. Simulation results show that the proposed eInP-RS scheme outperforms the standardized sensing-based SPS scheme in terms of the intra-platoon CAM/DENM delivery ratio and the average intra-platoon DENM delivery delay.

关键词： Simulation Merging Frequency conversion Dynamic scheduling Sensors Cams Delays Global communication Vehicle dynamics Collision avoidance

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